# Recent content by Hawkwind

Thanks for the link - interesting stuff. But I do not feel competent enough to comment on this.
2. ### What happens when an electron and positron collide

Of course, there is also the possibility of elastic scattering: Elastic scattering of electrons and positrons
3. ### Speed and mass

We know it from measuring the rest mass of a free electron - "free" means "unbound". In contrast to the photon, the electron does not move with a "natural velocity". Arbitrary speeds are possible - you should also remember that speed is relative, i.e. it also depends on the state of the...
4. ### Speed and mass

The 511 KeV correspond to the rest mass of the electron. When you accelerate it, it gains additional kinetic energy (1/2)*m*v^2 You may accelerate a particle which is lighter than the electron to a higher speed such that the above term for the kinetic energy will yield the same number...
5. ### What is Beta+ Decay

You are right: a free proton cannot beta decay. This can only happen in a nucleus where the binding energy of the child nucleus may compensate the loss of energy through the decay.
6. ### Speed and mass

KeV is "kilo electron volt": it is the amount of energy which an electron gains through acceleration by a voltage of 1000 V; see e.g. http://en.wikipedia.org/wiki/Electronvolt
7. ### Speed and mass

In principle, magnetic fields are helpful to measure the mass of a charged particle. A magnetic field exerts the Lorentz force on a moving charge; the resulting acceleration may be measured and is inverse to the mass of the electron. In practice, Penning traps are often used...
8. ### Speed and mass

Unfortunately, in the history of physics, the notion of a "relativistic mass" had been introduced. Nowadays, this is rather regarded as a kind of energy which increases inertia. "Relativistic mass" is not a scalar number as we may expect but a tensor: "relativistic mass" would vary with the...

I find it difficult to get a clue what you are asking about. Vertex functions appear in renormalizable field theories in higher order pertubation theory as corrections to vertices in Feynman diagrams. However, there is no such field theory dealing mesons as fundamental particles - the standard...
10. ### Gluons, where do they come from and where do they go?

For instance effective field theories like chiral pertubation theory could be a candidate: http://en.wikipedia.org/wiki/Chiral_perturbation_theory These are promising attempts to describe the low energy region of strong interactions, where QCD perturbation theory is not applicable. BTW, this...
11. ### Gluons, where do they come from and where do they go?

Getting curious: what exactly do you think is wrong in my post?
12. ### Gluons, where do they come from and where do they go?

Particles which carry the quantum number "colour" interact with each other by exchanging gluons ("strong force"). Proton and neutron however are neutral with respect to the colour quantum number. As already mentioned in other replys, the quarks do have colour - they are glued to each other by...
13. ### Why is the strength of weak nuclear force important ?

Well, the weak force is responsible for the beta decays. Thus, a larger coupling constant would result in reduced lifetimes of the decaying particles - e.g. the neutron. The beta decay also plays a role in the fusion process H + H -> He. In the 1st step, a deuterium nucleus will be formed p + p...
14. ### One dimensional Coulomb potential

You have to solve the exact equation. Finally, applying the boundary condition X(0) = 0 (because of the unfinite potential step) should deliver the discrete spectrum of solutions.
15. ### Faster than the speed of light

Agreed ... in order to illustrate your comment, I refer to Gell-Mann's book: "The Quark and the Jaguar" (http://www.amazon.com/dp/0805072535/?tag=pfamazon01-20)